This story by Thomas J. Sweeney appeared in The Irish American: May-June 2000 Edition.

This is a brief history of the Clan Sweeney taken from various sources including "Leabhair Chlainne Suibhne" (The Book of the Clan Sweeney) which was commissioned by Maire Mac Suibhne wife of Rory Mac Suibhne 10th Lord of Fanad (1472-1515). This manuscript is now in the Royal Irish Academy.

The Sweeneys, an Irish sept of the race of Ua Naill, can trace their ancestry from King Milesius of Spain through line of his son Heremon (King of Ireland; 1015-1028 BC). The sons of King Milesius were the legendary Celtic invaders of Ireland that conquered the land around 1000 BC.

Suibhne (Sweeney) is an OLD name, a very OLD name. In Irish it means pleasant and is pronounced SWIvNEYa. There are many High Kings associated with the history of the Sweeney name. There is Conn of the Hundred Battles, the 110th High King of Ireland. He was the mythical brother of Eogan, leader of the Gaelic tribes that settled in the midlands, Western and Northern areas of Ireland.

Others are:
- Eochiadh Muigl Mheadion (the Slave Lord) High King of Ireland from 358-366 AD. He received his nickname from the slave raids he led against the Romans in Britain. He died of natural causes in 366 at Tara, the home of the High Kings of Ireland. He married a Saxon princess named Carina whom he carried off in one of his raids.
- Naill Mor (Naill of the Nine Hostages) the youngest son of Eochiadh. This High King of Ireland was born around 357 died in 405. Naill asserted figurehead control over all Ireland after his sons overthrew the Ulidian kingdom in the north. Records show that he raided Britain and Gaul during the time of Theodosius the Great. In one of these raids, around 400 AD, he captured a young son of a noble family. After being sold to a land owner in the North of Ireland, the boy escaped I from his bondage and managed to return to his home in Britain. After, years of study and discipline he returned to Ireland to preach the gospel to the pagan Celts. His name was Patricius (Patrick). One of St. Patrick's first converts was Naill's son Conal.
- Eoghan, King of Aileach* and ruler of Tara in 425. He was personally baptized in 432 AD by Saint Patrick, along with his family. He died in 465.
- Suibhne Menn O'Neill (Sweeney the Renowned) monarch of Ireland from 616 to 628 AD.
- Flaithbertach An Trostan O'Neill (Flaherty of the Pilgrim's Staff) King of Aileach 1004-1030 and 1033-1036. In 1030 he went on a pilgrimage to Rome. In 1033 he returned and took over the Kingship after his son Aodh Athlone or Athlambh O'Neill was killed in battle. In 1036 he died and his Grandson Aodh Anrothan O'Neill (Hugh the Solitary) became King of Aileach and Prince of Ulster.

After a family dispute over the succession of the Aileach kingship, Anrothan O'Neill resigned and sailed to Scotland. There, according to the Book of Clan Sweeney, he acquired extensive lands in Argyll and married the heiress of Cowal and Knapdale, a princess from the Royal House of Argyll.

In the late 1100's, Suibhne Ruadh (the Red-haired Sween) is often mentioned in various pedigrees as being Toisech** of Knapdale. He was the great-grandson of Anrothan and is credited as being the builder of Castle Sween in Knapdale. This is reputedly the oldest stone castle in Scotland, whose ruins still stand on the shores of Loch Sween.

It was not until the coming of the Normans in the 12th century that Suibhne was adopted as a surname by the senior branch of the Ua Niall clan in Scotland. There too the name Loughlin originated, which survives to this day as the first name in the Sweeney family.

During their long stay in Scotland the Sweeneys maintained their Irish links. Maolmhuire Mac Sweeney married Beanmhidhe O'Conor (d.1269), granddaughter of King Rory O'Conor of Connacht.

The Sweeney family remained in Scotland until the 14th century, when they returned to Ireland having lost their lands in Argyll to Robert the Bruce in the battle of Bannockburn in 1314. These lands were granted to Sir John Menteith.

After the battle of Bannockburn there is no further mention of the Sweeney family in Scottish history. The Sweeneys of Castle Sween had returned to Ireland, where the senior branch went back to Rathmullan, almost in sight of the ancient (c. 1700 BC) stone fort, the Grianan of Aileach, from which they departed almost 200 years previously.

They divided into three branches: Mac Suibhne Fanad, Mac Suibhne na d'Tuatha and Mac Suibhne Banagh. Rathmullan was the seat of the Mac Sweeney Fanad for the next 400 years, during which time their influence extended from Donegal into Connacht and Munster. In Donegal their principle seats were Doe Castle and Rahan Castle near Killybegs.

In Scotland the inauguration of the Mac Suibhne chiefs had taken place at Iona, where they were also buried. In Ireland they were inaugurated in Kilmacrenan, County Donegal, where MacSuibhne Fanad had the privilege of sitting at the right hand side of The O'Donnell, Prince of Tirconnell. The remains of the Mac Sweeneys who returned to Ireland are interred outside the walls of Doe Castle, near Sheep Haven Bay. There is also a story that states a Clan Chieftain is buried in the walls of the Castle so there will always be a Mac Sweeney Chief in Doe Castle.

In 1497 a Sweeney Chieftain was at war with the O'Neill Chieftain of Tyrone. He asked for help from his
father-in-law in Scotland, who was Lord of the Isles. The Scottish Chief must have had his own problems because all he could spare were 187 Campbells, led by Alexander Campbell. This is the first reference to the Clan Campbell in Donegal.

The MacSweeney na d'Tuatha, or Mac Sweeney of the Battle Axes were so named because they were standard bearers of the O'Donnells, and chiefs of the Galloglasses (heavily armed Irish infantry). A branch of this family settled in County Cork, where they became commanders under The McCarthys, Prince of Desmond.

At the beginning of the 17th century, as with many old Irish nobility of Ulster, the Mac Sweeneys lost most of their lands in the plantation of the province. Their fine Doe Castle went to the Brook family, The Carmelite monastery of Rathmullan built by Ruadhri Mac Suibhne and his wife Maire O'Maille in 1516 to commemorate the death of their son, was taken by Bishop Knox who used it as his residence.

Following the expulsion of the Sweeneys from Donegal in the 17th century, a copy of the clan book was preserved by the Roddy family of Leitrim. In the 18th century the penal laws prevented the official recording of Catholic families - including the Sweeneys who remained Catholic. Some are recorded in Spain and France, but, unlike the earls in Ulster, the Sweeney family did not escape to Europe. In fact, Mac Sweeney Fanad opposed the "Flight of the Earls" from Rathmullan.

Leabhair Chlainne Suibhne (The Book of the Clan Sweeney) is a book of personal prayers and a family history .There is also a section dealing with the diseases and characteristics of that most important member of the medieval galloglass household, the horse.

Part of a copy of The Book of the Clan Sweeney was in the possession of the Chevalier Loughlin Sweeney family until early in the 19th century. It was lost when they were expelled from their property, Sweeney hill near Emo Park, by the Earl of Partarlington who wanted to extend his Monasterevan estate.

* Aileach was a large territory in the northern part of Ireland.
** Prime Minister.